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Suspension tuning.

9K views 41 replies 11 participants last post by  bacchus40 
#1 ·
I'm going to be going through my new to me f4i this winter and one of the things I'm really wanting to dial in for maintenance and tuning is the suspension. Anyone have any good resources/tips?
 
#2 ·
Do the fluids on the front and have a look at the rear shock. Those shocks aren't the best, I've got an 04 RR. The shock is pretty tired, it's best to replace
with a 2nd hand quality unit that's rebuilt IMHO. Just do fluids and try to set it up and see how it goes. THe suspension on them isn't that bad to be honest. My
newer GSXR 750 with inverted forks didn't seem to handle as well IMHO.
 
#3 ·
If I recal, you arent 200+lbs, so the stock springs should be ok for you. As Bandito says, change the fluids. As for tuning, honestly, the cheapest way is to do it yourself. Check out forums for the F4i, and see what other riders have set the rebound and compression at for a baseline. Setting your sag is pretty easy with a couple buddies. Plenty of videos online for that.

One good technique is to take your bike out for half a day on a bumpy twisty road, and back off all the clickers (full soft), then do it again full hard, then start adjusting them little by little). Its boring, but you learn alot
 
#4 ·
Thanks for these tips. I've been checking out a f4i subforum a bit on a cbr forum. But as with some forums there seems to be a lot to 'filter' through. From what I've read there's good odds that the rear shock isn't 'charged' anymore at this age. *Any thoughts on that?

I am about 185 so with gear on I'm probably 200+. But not a lot more.

I'll start I guess with servicing the forks and then trying to dial in the sag. *

I'm finding it harder to stay 'quiet' on this bike compared to my r3. Im really focusing on being steady but any bit of input from me or the road seems to cause movement in the bike. Not real bad, but just moreso then the 3. I'm not ruling out that the bike is just more sensitive and my skill is lacking, that I could be travelling a little more quickly/aggressively with it, or that the suspension isn't really set up well for me and may have been neglected to be serviced. The previous owner indicated he had set it up for himself(bigger/heavier guy)with the bags loaded so he thought it would be somewhat stiff for me.*

I guess it's time to start playing with the adjusters and seeing how the different settings feel. *
 
#5 ·
A stock R3 would have pretty compliant suspension. Most entry level bikes suspension I describe as riding a "wet pool noodle". It's more comfortable and
it's like riding a recliner around... it does make inputs to the bike not respond in the same way, and feels like it's soaking up all the pavement undulations
quite nicely.

The 600 will have suspension that can be setup much more firm. It's not super advanced suspension, but it's definately got a reasonable range of adjustment
for most folks. If the guy was heavy and carried around lots of stuff, he might have it setup very stiff. You'll want to figure out where it's currently set
and record that information for some reference maybe, but find more neutral settings to start with. Check the sag, check where the forks are set in the
triple clamps.
 
#6 ·
The info shared has pointed me in the right direction. I think miraculously the bike is set up to stiff for me right now mainly in the rear.*

Haven't had the time to start messing around with it. Between work, family, I've just been riding it instead when I have a chance. Soon though it's off the road for the winter. *
 
#7 ·
A sportbike properly setup will flow through the corners. It should not "turn in" too fast and you should not have to muscle it to turn. It's a delicate balance and once you have it, its a thing of beauty.

I pay a guy who knows what he's doing and its the best investment I've made in my bikes.
 
#9 ·
I'm not having troubles turning in. I'm having troubles with bumpiness/smoothness. I think any road imperfections are really getting magnified by the rear being set to stiff. The tires were like new when I got it.*

The front seems to soak things up decent but the rear is like a bit of a catapult.*

Tomorrow is my last day of insurance and then I'll have all winter to go over things. *I may try to soften the rear some tomorrow and try that out if I get a chance. *Might have to work though.*

im not ruling out paying someone to set it up for me. If I knew of someone I was confident in.
 
#12 ·
I'm not having troubles turning in. I'm having troubles with bumpiness/smoothness. I think any road imperfections are really getting magnified by the rear being set to stiff. The tires were like new when I got it.*

Tomorrow is my last day of insurance and then I'll have all winter to go over things. *I may try to soften the rear some tomorrow and try that out if I get a chance. *Might have to work though.*
It's not likely you can adjust to 'softer' suspension. The Hydraulics are going to slow it down or speed it up. the preload is just changing height. Unless the valving is closed its most likely a mechanical problem - you need a softer spring (current isn't moving enough) or stiffer spring (current is bottomed out)
 
#11 · (Edited)
Super cool vids.*

Interesting to me as I head down the rabbit hole that my gut instinct from riding it was correct, maybe a lucky guess but still somewhat validating that I can 'feel' what is going on.

I have zero rear static sag and barely any sag at all, have no one to help me measure but it's barely moving under my weight. Rear spring is one notch away from maxed out. I won't have a chance to really test things out this year. But I'm going to try and get things dialled in a bit atleast for sag and swap the fluid in the front forks. Should be a better starting point for the spring.*

Thanks again everyone for all the advice/input. I'm starting to just scratch the surface and see the light of how having a properly setup suspension will really transform this bike for me. Glad I'm starting to learn a bit and not just blundering on adjusting my riding to a improper setup.*
 
#13 · (Edited)
I'm clearly missing something here. Doesn't preloading the spring make the suspension stiffer? Same as adjusting the speed of the valving would make the suspension softer or harder? If it's all just speed of the valve or the spring is the spring what are the adjustments for exactly then?

In Dave moss's vid on setting rear static sag he talks about it being dangerous having no static sag due to the preload causing the bike to launch you out of the seat over bumps. *He describes it over and over to riders with no static rear sag on there bikes. It's like a 30min vid where he adjusts rear sag on countless bikes and describes what difference the adjustment will make. Within reason there would seem to be some adjustability within 'springs'. Only one rider did he describe being to heavy and needing a different spring and that the adjustment he was doing was merely a bandaid fix. And obviously that riders suspension was to 'soft' for his weight. Seems unlikely that at my weight of 185 I would need softer then stock suspension. From researching the f4i I should be heavy for the stock springs, to heavy by most all accounts. And outwardly atleast my suspension appears stock, same yellow spring on the rear that I've seen on all other f4i's in my searching. My rear spring is setup one step from as preloaded as it can go. *From what I saw on that vid it seems reasonable to me to adjust it down say two steps and see where my sag is at. I don't even really want to start playing with the valving until I have a further grasp on things. But the adjustment has a range of s-h, which i had assumed was soft to hard?

Maybe I'm using the wrong terminology, which wouldn't surprise me. Refer to my 'catapult' comment from earlier. That is exactly what I'm experiencing and I have zero static sag and barely any rear weighted sag either. Seems I'll be able to make a note able improvement by lessening my rear spring preload. Which I maybe wrongly translated or described as softening the suspension. *I'm just scratching the surface on all this I fully realize but somehow or other my bike is set up stiff. The rear is incredibly stiff and the front seems fairly stiff too although I haven't even been trying to wrap my head around the front end yet.*
 
#16 · (Edited)
is the rear spring not progressive or variable rate? So preloading it should affect the stiffness, no?

https://m.youtube.com/watch?v=3FeZJRiAXRkThis is the vid I was referring to. **https://m.youtube.com/watch?v=3FeZJRiAXRk
*

what he shows/refers to in the first handful plus of bikes is exactly how my bike is, no static sag. Beyond that I believe the adjusters for the valving are turned to hard as well, or slow as you would maybe call it? This combination seems like it is making for a stiff suspension and a rear that wants to unseat me. Before I buy new springs or valves it seems logical to me to reduce preload and adjust the existing valving to the softer settings?
 
#18 ·
I can follow you that the preload affects the height but it also affects the sag no? *Which is directly related I believe to the stiffness? *So a buy product of decreasing preload/height is a increase in sag and essentially less stiffness of the suspension? *Having little to no rear sag is angling my bike forward I think and making the rear suspension act stiffer, no? *That's besides the inherent negative handling characteristics that that imbalance gives to I think? *Oversteer?
*
I'm not trying to be defensive, I'm just trying to learn. If I thought I could or did know it all from watching a couple of you tube vids I'd not have started this thread. *
 
#19 ·
I'm really trying to wrap my head around this preload thing. So when you preload a spring you don't make it stiffer but it then requires more force or weight to compress it further? *So right now with the rear of my bike adjusted up to no static sag I 'feel' the bike is stiffer because of the incorrect geometry, the shock travelling in a more limited range because of it being 'topped' out and the spring requiring more force or weight input to get it to travel fully, and my suspension having no or very little downward travel range to soak up road irregularities and for braking traction. Also reduced braking from the geometry angled forward if the front preload isn't as stiff?

Is this somewhat on the right path of thought?*

My brain hurts. Thank god ive got all winter to hopefully wrap my head around this. *Or If I can't atleast I'll know and have the time to pay someone who does before spring.*
 
#20 · (Edited)
I've read a few things now that say that preload doesn't affect stiffness. But this video would seem to imply that on a progressive rear spring preload does affect spring rate. That only on a linear spring would it not? And even then it still affects the stored energy of the spring, so while not technically stiffer preloading it still requires more force for further movement.

https://m.youtube.com/watch?v=Bs0uEWmrrLQ*
 
#22 · (Edited)
Your stock spring is most likely linear rate. Increasing preload doesn't change the spring rate, however it does move the force required to initiate compression further up the linear curve. This is best envisioned with a graph: https://www.sportrider.com/technicalities-spring-rate-and-preload#page-2

On the topic of preload and mentioned earlier, not only will changing preload affect the force needed to initiate spring compression, but depending on how much preload you setup, can change the character and balance of the bike. This is affected by either changing rake (increased rear preload, rear end is elevated relative to front, trail is decreased), and concomitantly, droop travel will be affected as well. By how I've read it, it seems like you have too much preload in the back at the moment and so if I were in your position, I would back preload out a few turns. You want your bike to have both static sag and loaded sag; for the street, I would run 1/4 to 1/3 of my absolute suspension travel as loaded sag, deferring to more sag if you're riding rougher roads.

Note that as you change sag, you should also be changing your dampening adjustments as well, especially rebound. If I were in your position, I would do as suggested previously and back out rear preload and ideally have it adjusted with proper front/rear static and loaded sag, and then run the bike with all clickers fully out (soft). Then run your normal roads and slowly increase the dampening until you achieve something that is favorable; I personally shoot to have the bike as soft as possible for street riding while minimizing front/back oscillations. Obviously this will change depending on surface conditions and the pace at which you ride. Hope that helps a bit.
 
#23 ·
All of this helps. I just need some time now to start messing with it all.*

I've got a board in my shop I'm going to record all the settings I've started with and then start adjusting/recording my changes.

If in the end I can't get the bike to a decent place myself I'll look for professional help. *and if it comes to that point hopefully I'll have a basic enough understanding to know what they're going to do for me. *
 
#26 ·
Yes thanks to everyone who chimes in. I believe my rear spring is linear, the first two coils are kind of closer but all the rest look evenly spaced and the diameter of the spring doesn't appear to change.*

I've been stocking my shop with firewood most of the day and trying to motivate myself to repair the exhaust on my truck. *Ive taken a few moments here and there to have a quick look at the bike but the honeydew list is to long right now to dive into it seriously. Winter is coming fast.
 
#27 · (Edited)
Static sag is the weight of the bike reflected on an unloaded spring. There should be range of movement (setting) available somewhere. If you get no static sag on an un-preloaded spring your spring is too stiff.
No static sag via cranked up preload, means there is stored energy in the spring as it returns to length with more force than the bike weighs ... the catapult. PO had bags on it?
Rider sag is the bike and rider with gear, there should be a range of movement (setting) available somewhere...
Rider sag can be adjusted to affect the steering, less sag/quicker steering, more sag/slower steering.

Try backing off the preload, see if you can get the static sag, then go for the rider sag ... at least you'll find out if the spring is correct (probably good enough)
The damping is just controlling the speed of the spring movement.
Take the spring off the shock, compress the shock and see if it returns to full extended length, if not, it's probably lost it's gas charge...
 
#28 ·
To update this. And again thanks everyone for trying to edumacate me and help me out.*

I learned how to adjust my basic suspension settings. Both my front and rear preloads were maxed out(rear might have been one notch from max, fronts were buried) when I got the bike and backing both of those off/out solved most all of my issues. I'm sure there's plenty of fine tuning that could be done. But in the end I found some old info on a cbr forum where a guy close to my weight on stock suspension posted up his settings and that's what I moved mine to and have just left them there for now. Reset the compression and rebound as well as the fronts weren't adjusted evenly, all over the map.

No launching out of the seat on bumps. And the suspension 'feels' good to me.*
 
#29 ·
i was half way thru reading your post as i started to respond. yes its common for folks to max out their
pre-load instead of getting the correct spring rate for their particular application. I dont know if its a young
cbr thing but i've heard it most from cbr600 guys. i never owned one so i dont know either way
 
#30 ·
Interesting. Backing things off some seems to have helped a lot for me. And I'm not light about 180pds. I'm not ripping this thing on a track either though, although I do enjoy some spirited road riding. I have no doubts I couldn't still benefit greatly from a tuned suspension and springs of the proper rate specifically for me.*

For now though I'm much happier with it than I was. *
 
#31 ·
At 180lbs, the stock springs should be fine for you. Best thing for you to do now is "tune your own". Grab your screwdriver, set everything to wide-open, go ride a section of bumpy twisty road for 10mins, stop, set everything to fully closed, repeat. Make a strong mental note of how the bike behaves differently. Then, set everything to 2-clicks from open, and 2 clicks from closed, repeat. That should give you an idea how extreme settings make the bike handle differently.

Using those three reference points, its now just a question of 1-2 clicks in either direction, which is best done out on a longer ride.
 
#32 · (Edited)
At 180lbs, the stock springs should be fine for you. Best thing for you to do now is "tune your own". Grab your screwdriver,.
i was thinking the same thing.. thats pretty good weight for any sport-bike . Should be within adjustment range :D

but instead of flying blind for a few hundred kilometers I suggest you go look up your bike HERE op!!

this will get you going in the right direction and then you can make small adjustments one way or the
other.. if our calculations are correct you're likely within a few clicks.. Back in the day Sport Rider Magazine
would do yearly reviews of new model bikes and came up with a list of recommended starting points.

you are looking for a poised ride, one in which the chassis is not upset under normal riding
conditions, rear of bike balanced with front and vice versa.. front end dive is no fun.

https://www.cycleworld.com/sport-rider/suggested-sport-bike-motorcycle-suspension-settings/


Suggested Sport Bike Motorcycle Suspension Settings

Sport Rider's setup recommendations for every motorcycle tested from 1997
November 17, 2009

These tables show suggested suspension settings for each bike tested by the Sport Rider staff. Scroll down for your brand/model of bike. You can also use the tables to find which issues of Sport Rider each bike was tested. For more information about suspension setup, visit our Sportbike Suspension Guide, which has a setup guide, a suspension tuning guide, and links to various useful articles on the site.
 

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#35 · (Edited)
ahh yes i forget nobody does maintenance on forks.. ever :D

all i mean is literally, a starting point. I think its easy to forget when you 1st started playing with
suspension, you also didnt know how each setting affected another.

if you start with an informed 'setup' you will learn much quicker how far not to go in one direction or another..
you'd still start with a way more balanced ride than if going it alone i would think.


if all that fails, you could just service the stupid bike before you ride it :flip :canadian

:coffee
 
#34 · (Edited)
All good info, suggestions and observations.*

Here is what I'm at right now:

Front Preload: 3 lines showing Front Rebound: 1.50 turns out Front Compression: 1.25 turns out
Rear Preload: position 5 Rear Rebound: 1 turn out Rear Compression: 1.5 turns out

These were settings I 'stole' off the Internet. My old f4i is turns, no clicks.

I think I will take the time to play around with them some. Probably even take them to the extremes to see the differences. *

I'll definetly have a look at the cycleworld settings too.

And yes Chia I have no doubt that my suspension is pretty bagged out and in need of some serious servicing/repair. But I've got to work with what I've got right now. Had hoped to go through it last winter but life got in the way.

Thanks again for all the input. It's appreciated. *
 
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